1. Field of the Invention
The invention relates to the technical field of digital content protection and, more particularly, to a proprietary portable audio player system for protecting digital content copyrights.
2. Description of Related Art
Since the semiconductor processes have developed rapidly, electronic products have the enhanced functions and follow the light, thin and miniature trend.
The increasing portable audio players further allow digital music to have the features of mobility and personalization. The digital music is essentially divided into two format types, i.e., a general MP3 format and a proprietary online music format, in accordance with the applied compression technique and the technical spreadability. The general MP3 digital music can be shared and distributed easily but also cause an argument about the copyright infringement easily, which is inverted on the proprietary digital music.
As the MP3 music and the digital content dramatically sprout, the online digital music services are considered to be an important trend in the future. Accordingly, the digital music copyright is becoming more and more important. A peer-to-peer online music access mode allows a user to enjoy and share music files with others. However, such a mode can easily cause an argument about music copyright infringement.
To overcome this, U.S. Pat. No. 7,039,615 granted for Gajjala et. al. for “Retail Transactions Involving Digital Content in A Digital Rights Management (DRM) System” has disclosed a platform of digital rights management (DRM) software to overcome the problem of digital music copyright infringement.
The DRM software links a user end through a server. Each song has a content key. Namely, when a song is downloaded from the server to the user end through the Internet, the content key corresponding to the song is also downloaded. The content key obtained in each download is the same for a same song. Each music file can be played as the content key is met. Accordingly, while a content key is transmitted to obtain, a public key and a private key are applied for protection from being cracked.
The DRM software has the advantage of safely transmitting a digital content subscribed by a user and playing the digital content on a designated computer, portable device or network device, and the disadvantage of requiring an additional public key for protecting the content key in transmission. In addition, additional operations for a received music file and associated content keys are required, which can easily cause the insert-in playback delay on playing a song.
As cited, the content key corresponds to a specific song, and an encryption mechanism, such as using the public key and private key, is applied to the content key for protection. However, if the encryption mechanism is cracked, the content key can be obtained arbitrarily, and the song is not protected anymore. The DRM software can protect the digital content copyright by using the standard compression format and the public key and the private key, which is insufficient in security and efficiency. In addition, such a protection limits a user at the rights of sharing digital content files. Therefore, an improved protection mechanism is required.